hg2git.py: Add support for extracting authorship from Signed-off-by lines

Unfortunately, it's not configurable yet (read: cannot be disabled) as
it may take some time to match against regex all the time (especially
from some initial import).

This also enables cleaning up usernames by stripping silly leading and
trailing chars like '"' (which is the only one supported ATM).

Signed-off-by: Rocco Rutte <pdmef@gmx.net>

hg2git.py

@@ -13,8 +13,12 @@ import re
 import sys
 import os
 
+# silly regex to catch Signed-off-by lines in log message
+sob_re=re.compile('^Signed-[Oo]ff-[Bb]y: (.+)$')
 # silly regex to see if user field has email address
-user_re=re.compile('[^<]+ <[^>]+>$')
+user_re=re.compile('([^<]+) (<[^>]+>)$')
+# silly regex to clean out user names
+user_clean_re=re.compile('^["]([^"]+)["]$')
 # git branch for hg's default 'HEAD' branch
 cfg_master='master'
 # insert 'checkpoint' command after this many commits or none at all if 0
@@ -28,21 +32,36 @@ def setup_repo(url):
   myui=ui.ui()
   return myui,hg.repository(myui,url)
 
+def fixup_user(user,authors):
+  if authors!=None:
+    # if we have an authors table, try to get mapping
+    # by defaulting to the current value of 'user'
+    user=authors.get(user,user)
+  name,mail,m='','',user_re.match(user)
+  if m==None:
+    # if we don't have 'Name <mail>' syntax, use 'user
+    # <devnull@localhost>' if use contains no at and
+    # 'user <user>' otherwise
+    name=user
+    if '@' not in user:
+      mail='<devnull@localhost>'
+    else:
+      mail='<%s>' % user
+  else:
+    # if we have 'Name <mail>' syntax, everything is fine :)
+    name,mail=m.group(1),m.group(2)
+
+  # remove any silly quoting from username
+  m2=user_clean_re.match(name)
+  if m2!=None:
+    name=m2.group(1)
+  return '%s %s' % (name,mail)
+
 def get_changeset(ui,repo,revision,authors):
   def get_branch(name):
     if name=='HEAD':
       name=cfg_master
     return name
-  def fixup_user(user,authors):
-    if authors!=None:
-      # if we have an authors table, try to get mapping
-      # by defaultung to the current value of 'user'
-      user=authors.get(user,user)
-    if user_re.match(user)==None:
-      if '@' not in user:
-        return user+' <none@none>'
-      return user+' <'+user+'>'
-    return user
   node=repo.lookup(revision)
   (manifest,user,(time,timezone),files,desc,extra)=repo.changelog.read(node)
   tz="%+03d%02d" % (-timezone / 3600, ((-timezone % 3600) / 60))
@@ -105,12 +124,50 @@ def get_filechanges(repo,revision,parents,mleft):
     l,c,r=outer_set(mleft,mright,l,c,r)
   return l,c,r
 
+def get_author(logmessage,committer,authors):
+  """As git distincts between author and committer of a patch, try to
+  extract author by detecting Signed-off-by lines.
+
+  This walks from the end of the log message towards the top skipping
+  empty lines. Upon the first non-empty line, it walks all Signed-off-by
+  lines upwards to find the first one. For that (if found), it extracts
+  authorship information the usual way (authors table, cleaning, etc.)
+
+  If no Signed-off-by line is found, this defaults to the committer.
+
+  This may sound stupid (and it somehow is), but in log messages we
+  accidentially may have lines in the middle starting with
+  "Signed-off-by: foo" and thus matching our detection regex. Prevent
+  that."""
+
+  loglines=logmessage.split('\n')
+  i=len(loglines)
+  # from tail walk to top skipping empty lines
+  while i>=0:
+    i-=1
+    if len(loglines[i].strip())==0: continue
+    break
+  if i>=0:
+    # walk further upwards to find first sob line, store in 'first'
+    first=None
+    while i>=0:
+      m=sob_re.match(loglines[i])
+      if m==None: break
+      first=m
+      i-=1
+    # if the last non-empty line matches our Signed-Off-by regex: extract username
+    if first!=None:
+      r=fixup_user(first.group(1),authors)
+      return r
+  return committer
+
 def export_commit(ui,repo,revision,marks,heads,last,max,count,authors):
   (_,user,(time,timezone),files,desc,branch,_)=get_changeset(ui,repo,revision,authors)
   parents=repo.changelog.parentrevs(revision)
 
   wr('commit refs/heads/%s' % branch)
   wr('mark :%d' % (revision+1))
+  wr('author %s %d %s' % (get_author(desc,user,authors),time,timezone))
   wr('committer %s %d %s' % (user,time,timezone))
   wr('data %d' % (len(desc)+1)) # wtf?
   wr(desc)